Which of the following statements indicates

Which of the following statements indicates that the law of multiple proportions is

being followed.

(i) Sample of carbon dioxide taken from any source will always have carbon

and oxygen in the ratio 1:2.

(ii) Carbon forms two oxides namely CO2 and CO, where masses of oxygen

which combine with a fixed mass of carbon are in the simple ratio 2:1.

(iii) When magnesium burns in oxygen, the amount of magnesium taken

for the reaction is equal to the amount of magnesium in magnesium

oxide formed.

(iv) At constant temperature and pressure, 200 mL of hydrogen will combine

with 100 mL oxygen to produce 200 mL of water vapour.